This application claims priority of Japanese Application No. P2000-081857 filed Mar. 17, 2000, the disclosure of which is hereby incorporated by reference herein.
This invention relates to a data recording/reproducing device for recording data and reproducing the recorded data.
Conventionally, in a recording/reproducing device having a tape-like recording medium such as a VTR (video tape recorder), it is often the case that a synchronizing signal to be used is switched between recording and reproduction. That is, in the conventional recording/reproducing device, it is often the case that, at the time of recording, a synchronizing signal is generated from an input video signal so as to carry out the recording operation in accordance with the synchronizing signal, whereas, at the time of reproduction, a reference signal is generated by a built-in crystal oscillator so as to carry out the reproducing operation in accordance with the reference signal.
On the other hand, in a recording/reproducing device having a disc-shaped recording medium, the recording operation and the reproducing operation are often carried out at the same time. Therefore, in such devices, unlike the devices having a tape-like recording medium, either the synchronous system processing sections for generating the synchronizing signal and the reference signal must operate independently for recording and for reproduction, or the reproducing operation must be synchronized with the recording operation.
As described above, in recording/reproducing devices having a disc-shaped recording medium, where different synchronous system processing sections are used for recording and for reproduction, thus making the synchronous systems operate asynchronously, an image to be displayed is interrupted and becomes discontinuous when shifting from the display of an image being recorded to the display of an image being reproduced, and it is difficult to simultaneously display an image being recorded and an image being reproduced. The display is also disrupted when displaying an OSD (on-screen display) superposed on an image.
Where the recording operation is synchronized with the reproducing operation, synchronization of an image and sound may not be fixed as a frame synchronizer is used. That is, when a video signal to be input and recorded on the disc becomes unstable, encoding is temporarily stopped and synchronization between encode processing of video data and encode processing of audio data cannot be realized. Therefore, the video data and audio data are shifted from each other at the time of recording.
In contrast, where the reproducing operation is synchronized with the recording operation, the reproducing operation may be influenced by the recording operation. That is, when the recording operation becomes unstable as a video signal to be input from outside and recorded on the disc is irregularly input, the reproducing operation becomes unstable, too, and the video signal cannot be reproduced stably.
Furthermore, in the recording/reproducing device having a function to record input data and simultaneously reproduce the data, if a recording system processing section and a reproducing system processing section are asynchronous, the time difference between recording data and reproducing data is not fixed, but may vary.
Thus, in view of the foregoing status of the art, it is an object of the present invention to provide a data recording/reproducing device which enables stable switching between output of data to be recorded and output of data to be reproduced, even in the case where independent synchronous systems are used for the recording operation and for the reproducing operation.
A data recording/reproducing device according to the present invention includes a video signal recording unit operable to record an input video signal onto a recording medium; a video recording synchronous controller operable to generate a video recording clock and to control the timing of recording processing carried out by the video signal recording unit in accordance with the video recording clock; an audio signal recording unit operable to record an input audio signal onto the recording medium; an audio recording synchronous controller operable to generate an audio recording clock and to control the timing of recording processing carried out by the audio signal recording unit in accordance with the audio recording clock; a video signal reproducing unit operable to reproduce a video signal recorded on the recording medium; a video reproduction synchronous controller operable to generate a video reproduction clock and to control the timing of reproducing processing carried out by the video signal reproducing unit in accordance with the video reproduction clock; an audio signal reproducing unit operable to reproduce an audio signal recorded on the recording medium; an audio reproduction synchronous controller operable to generate an audio reproduction clock and to control the timing of reproducing processing carried out by the audio signal reproducing unit in accordance with the audio reproduction clock; a storage device operable to store a recording video signal to be recorded onto the recording medium by the video signal recording unit; and an output controller operable to read out the recording video signal recorded in the storage device when switching and outputting a reproduction video signal to be reproduced by the video signal reproducing unit and the recording video signal to be recorded by the video signal recording unit.
A recording/reproducing device according to the present invention is adapted for recording and reproducing a video signal and an audio signal. The device includes an encoding circuit for encoding an input video signal and an input audio signal; a recording/reproducing circuit for recording the encoded video signal and the encoded audio signal onto a recording medium and for reproducing the recorded video signal and the recorded audio signal; a decoding circuit for decoding the reproduced video signal and the reproduced audio signal; a recording synchronous circuit for generating a recording clock for processing the encoded video signal and the encoded audio signal, and for controlling the timing of recording processing carried out by the recording/reproducing circuit on the basis of the recording clock; and a reproduction synchronous circuit for generating a reproduction clock for processing the reproduced video signal and the reproduced audio signal, and for controlling the timing of reproduction processing carried out by the recording/reproducing circuit on the basis of the reproduction clock; wherein the recording clock for processing the encoded audio signal by the recording synchronous circuit and the reproducing clock for processing the signal by the reproduction synchronous circuit are synchronized with each other.
A recording/reproducing device according to the present invention is adapted for recording and reproducing a video signal and an audio signal. The device includes an encoding circuit for encoding an input video signal and an input audio signal; a recording/reproducing circuit for recording the encoded video signal and the encoded audio signal onto a recording medium and for reproducing the recorded video signal and the recorded audio signal; a decoding circuit for decoding the reproduced video signal and the reproduced audio signal; a recording synchronous circuit for generating a recording clock for processing the encoded video signal and the encoded audio signal, and for controlling the timing of recording processing carried out by the recording/reproducing circuit on the basis of the recording clock; a reproduction synchronous circuit for generating a reproduction clock for processing the reproduced video signal and the reproduced audio signal, and for controlling the timing of reproduction processing carried out by the recording/reproducing circuit on the basis of the reproduction clock; a storage circuit for storing the input video signal; and a switching circuit for switching and outputting the stored video signal output in accordance with the reproduction clock and the reproduced video signal from the decoding circuit.